1. Field of the Invention
This invention relates to antimicrobial activity, and, more specifically, relates to antimicrobial cleansing compositions including chlorhexidine and a nonionic surfactant.
2 Background of the Invention
The antimicrobial effects of bisbiguanides have long been known. Chlorhexidine is the best known member of the class, and this product has been marketed for many years in various formulations such as antibacterial hand washes and surgical scrub compositions. These formulations generally include both a surface active agent and a low percentage of an alcohol, usually isopropanol.
Burdon et al. reported in 1967 that stock solutions of chlorhexidine frequently were contaminated with species of Pseudomonas, but that the combination of chlorhexidine and 4% V/V isopropanol greatly reduced this problem. Nevertheless, the authors speculated that continued use of isopropanol may ultimately result in selection of strains resistant to the chlorhexidine-isopropanol combination.
Billany et al., in U.S. Pat. No. 3,960,745, discloses a chlorhexidine cleansing composition formulated with a polyoxyethylene-polyoxypropylene nonionic surfactant. The Billany et al. formulation is marketed under the trade name Hibiclens.RTM. by Stuart Pharmaceuticals, Wilmington, Del., a division of ICI Americas Inc. Billany et al. teaches that anionic, cationic and amphoteric surfactants all form complexes with chlorhexidine, and that of 17 nonionic surfactants studied, only four, all polyoxyethylene-polyoxypropylene surfactants, could be formulated with chlorhexidine with retention of 70% of the antimicrobial activity of a 2% solution of chlorhexidine gluconate. The patent further teaches that not even all members of this class are equally suitable for chlorhexidine formulations, and that complexation of the chlorhexidine with the surfactant results in a substantial reduction of the antibacterial activity of the chlorhexidine.
U.S. Pat. No. 4,420,484 to Gorman et al. discloses a skin cleansing composition consisting of a bisbiguanide antimicrobial agent and a combination of surfactants formulated with water, alcohol and various other ingredients. The Gorman et al. patent states that all ingredients in the patented composition are particularly described in the prior art.
Owens, in U.S. Pat. No. 4,456,543 shows an antibacterial cleansing product containing a bisbiguanide and one or more nonionic polyoxyalkylene surfactants containing oxyethylene, oxypropylene and oxybutylene blocks. Owens, like Billany et al., states that complexation of chlorhexidine and the surfactant results in a substantial reduction of antibacterial activity.
Chlorhexidine-containing compositions are marketed by Stuart Pharmaceuticals, Wilmington, Del., under the trade name Hibiclens.RTM.; by Xttrium Laboratories, Inc., Chicago, Ill., under the trade name Exidine.RTM., by Medical Systems Research, Inc., Salt Lake City, Utah, under the trade name Steri Stat and by Huntington Laboratories, Inc., Huntington, Ind., under the trade name Cida-Stat.
Chlorhexidine cleansing compositions are used principally as hand washes and surgical scrubs. As such, it is desirable to effect the most complete kill possible of the bacterial flora which routinely proliferate on the skin. The principal organism existing on the skin is Staphylococcus aureus, an organism well-known to be resistant to antibacterial agents. Accordingly, there is a need for a chlorhexidine composition particularly effective against this organism. This invention addresses this and other needs.